ST. PAUL, Minn. (AP) - Federal officials have again denied Gov. Mark Dayton's request for more time to comply with stronger driver's license standards to board planes.

Minnesota hasn't upgraded its licenses to meet the requirements of the Real ID Act. That has raised concern that Minnesotans may need an extra form of ID to board a domestic flight in 2018.

Dayton wrote to the Department of Homeland Security in April seeking a compliance extension until 2020.

On Friday, department officials responded that Minnesota still hasn't done enough to merit an extension. Bills to set the required upgrades in motion are still in the works at the Legislature.

Federal officials say the state can renew its extension request once lawmakers pass legislation allowing for REAL ID implementation.